1. Field of the Invention
The present invention relates to processes and intermediates for preparing 4-[2-(2-fluorophenoxymethyl)phenyl]piperidine compounds having activity as serotonin (5-HT) and norepinephrine (NE) reuptake inhibitors.
2. State of the Art
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage (International Association for the Study of Pain (IASP), Pain Terminology). Chronic pain persists beyond acute pain or beyond the expected time for an injury to heal (American Pain Society. “Pain Control in the Primary Care Setting.” 2006:15). Neuropathic pain is pain initiated or caused by a primary lesion or dysfunction in the nervous system. Peripheral neuropathic pain occurs when the lesion or dysfunction affects the peripheral nervous system and central neuropathic pain when the lesion or dysfunction affects the central nervous system (IASP).
Several types of therapeutic agents are currently used to treat neuropathic pain including, for example, tricyclic antidepressants, serotonin and norepinephrine reuptake inhibitors, calcium channel ligands (e.g., gabapentin and pregabalin), topical lidocaine, and opioid agonists (e.g., morphine, oxycodone, methadone, levorphanol and tramadol).
The 4-[2-(2-fluorophenoxymethyl)phenyl]piperidine compounds described herein inhibit the reuptake of both serotonin and norepinephrine by binding to the serotonin and norepinephrine transporters. A need exists for an efficient process of preparing such compounds.